This invention relates to control center for accommodating a multitude of plug-in type control units superposed on one another therein, and more particularly to a shutter device for each of those control units.
Control centers of the type referred to include the box member provided on the central portion with a set of vertical buses and a multitude of superposed control units removably accommodated on each of the front and rear sides of the vertical buses within the box member. Each of the control units is provided on the rear surface with a plurality of protruding connectors arranged to be connected in plug-in manner to associated one of the vertical buses when the control unit is inserted into the final accommodated position. Those control units can be drawn out from the box member for purposes of maintenance, inspection etc. At that time the vertical buses alive are prevented from being exposed by a protective barrier for covering the entire area of the vertical buses. The protective barrier is provided with a multitude of openings through which the associated protruding connectors extend one for each connector.
In order to improve the security, the control unit has been recently provided with a shutter device respective to the insertion and removed thereof into and from the box member to automatically open and close the abovementioned openings.
One of conventional shutter devices has comprised a lever arm rotatably supported to a frame of a box member and a shutter plate slidably disposed on a protective barrier, for each control unit the arrangement being such that the lever arm can be rotated by one part of an associated control unit to interlock the shutter plate (see, for example, Japanese laid-open utility model application No. 170,808/1980).
In the conventional shutter device as described above positions of the protective barrier including the shutter plate, the frame of the box member having the lever arm supported thereto and the control unit driving the lever arm relative to one another might not be registered with one another due to errors in their assemblings. In addition, any control center has many chances of relacing one by another of control units whereupon the adjustment has been required.
Also, in order to permit the rotation of the lever arm reaching the associated shutter plate located within the vertical bus compartment, it has been required to dispose a through hole on a partitioning wall for the vertical bus compartment and further it has been necessary to form a spacing between the protective barrier and the partitioning wall thereby to cause the shutter plate interlocking with the lever arm to slide in the spacing. Thus the vertical buss compartment has not be good in air tightness. Also the shutter device has been required to be more inexpensive because the control center has a large number of the control units accommodated therein.
Accordingly it is an object of the present invention to eliminate the disadvantages of the prior art practice as described above by the provision of a shutter device for a control unit including a shutter plate arranged to be directly driven by a connector protruding beyond the rear surface of the control unit.